<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .container{
      border: 10px solid skyblue;
      /* overflow: hidden; */
    }
    .left {
      background: red;
      width: 200px;
      height: 200px;
      float: left;
    }
    .clear {
      clear: both;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="left">
      i love kgt
    </div>
    <div class="clear"></div>
  </div>
</body>
</html>